Five states and the Gulf of Mexico produce more than 80% of U.S. crude oil

Five states and the Gulf of Mexico supplied more than 80%, or 6 million barrels per day, of the crude oil (including lease condensate) produced in the United States in 2013. Texas alone provided 35%, according to preliminary 2013 data released in EIA's March Petroleum Supply Monthly. The second-largest state producer was North Dakota with 12% of U.S. crude oil production, followed by California and Alaska at close to 7% each and Oklahoma at 4%. The federal offshore Gulf of Mexico produced 17%.

Total U.S. crude oil production grew 15% in 2013 to 7.4 million barrels per day. Texas and North Dakota led that growth, with their crude oil outputs increasing 30% and 29%, respectively, from 2012. Production gains in both states came largely from shales, especially the Eagle Ford in Texas and the Bakken in North Dakota. In the three years since 2010, North Dakota's crude oil output has grown 177% and Texas's output 121%, the fastest in the nation.

Three other states that were among the top 10 U.S. producers in 2013 also experienced production growth rates above 20% during the past three years. Colorado, which overlies part of the Niobrara Shale, had 93% growth in production from 2010 to 2013; Oklahoma, with the Woodford Shale, had 62% growth; and New Mexico, which shares the Permian Basin with Texas, had 51% growth.

Crude oil is produced in 31 states and two offshore federal regions—the Gulf of Mexico and the Pacific Coast. Of those 33 producing areas, 10 supply more than 90% of U.S. output. While 9 of those top 10 areas were also among the top 10 producers five years ago, their relative contributions have changed.

North Dakota has risen from the seventh largest oil producer to the second. The Gulf of Mexico, Alaska, and California, which together in 2008 supplied nearly half of U.S. crude production mainly from conventional oil reservoirs, provided less than one-third of national output in 2013. Output in those areas has declined at the same time that overall national production has expanded.